Due to a recent technological development in a microprocessor and a networking represented by internet system, the information communicating devices such as a personal computer or a portable telephone connected with a communication network are widely used. Although a built-in dock in each device is synchronizing with a dock in its own device, a time error of the dock in each device usually exists. Therefore, an exact time can't be displayed, and an inconsistency of time among the devices arises when an information is exchanged from device to device through the communication network.
Up to now for example, it is a usual method to correct a time lead or lag manually by hearing a telephone service of a time signal by NTT (a name of the Japanese telephone and the telegram company).
However, in this method of making use of the time signal by the telephone, it is troublesome for a user to make a manual correction, and is not always easy to secure a correctness of time. Moreover, recently a communication through a network represented by internet is widely used, and each device is becoming an element of the network system such as configured with a telephone line., rather than a stand-alone device. Under these circumstances, it is very convenient if the clock built in each device can be automatically corrected by utilizing the network system instead of hearing the time signal by the telephone.
To cope with the problem, a time correction system utilizing a GPS satellite is being considered, wherein a GPS means a geographical positioning system. A configuration of the time correction system as a prior art is shown in FIG. 7. In this FIG. 7 an inputting part 1 is for inputting a GPS data transmitted from the GPS satellite, a receiving means 2 is for receiving the GPS data through the inputting part 1 for obtaining a GPS time, and a data converting means 3 is for converting the GPS time obtained in the receiving means 2 to an information which is comparable with an internal clock. A time generating means 4 is for generating a time as the internal clock, and a time displaying means 5 is for displaying the time generated by the time generating means 4. A time data comparing and judging means 6 is for comparing the time generated by the time generating means 4 with the GPS time, and judges whether or not a time error exists in the time generating means 4. A time correcting means 7 is for correcting a time if the time error eats in the time generating means 4, and corrects the internal clock by informing the time generating means 4 of the time to be corrected. The time correcting means 7 is also provided with a forcible correcting function 8 for a user to forcibly correct the internal dock. A transmitting means 9 is for transmitting a time correcting command to an external device such as a personal computer connected to the network system.
In a system configured as mentioned above, it becomes possible to correct the time by utilizing the network system including a device for receiving a GPS signal. However, in the system of this kind including a host machine for receiving the GPS signal, an incessant monitoring of a state of GPS and the internal clock is required. Therefore, a problem also arises wherein a processing load of the host machine becomes high since the time correction command has to be delivered to each device of the network system.